Synthesis and Characterization of Chrysin-Loaded β-Cyclodextrin-Based Nanosponges to Enhance In-Vitro Solubility, Photostability, Drug Release, Antioxidant Effects and Antitumorous Efficacy

Chrysin is a naturally-occurring flavone in many plants and exhibits various biological activities; however, it has limited aqueous solubility. In an attempt to improve aqueous solubility, in the present study, we sought to formulate an effective nano-carrier for chrysin by using hyper-branched beta-cyclodextrin (beta-CD)-based nanosponge (NS) polymers. Complexes of chrysin were prepared with three types of NS polymers derived from different cross-linking ratios (1: 2, 1: 4 and 1: 8) of beta-CD and diphenylcarbonate. The chrysin-NS-1: 8 formulation appeared to exhibit the greatest efficiency in the context of drug-loading potency, in-vitro drug-release, in-vitro dissolution profile, in-vitro photostability effect and antioxidant potential. Differential scanning calorimetry, X-ray powder diffraction and Fourier transform infrared spectroscopy studies confirmed the interactions of chrysin with chrysin-NS-1: 8 complexes. The particle size of the chrysin-loaded NS formulation was around 450 nm, with high polydispersity indices. The zeta potential value was sufficiently high (-38.4 mV) to obtain a stable nanosuspension. The chrysin-NS-1: 8 complexes also exhibited more potent anti-tumorous activity in HeLa cells than that of plain chrysin. Thus, this nano-carrier for chrysin appears potentially useful to employ in biological systems for its optimal antioxidant and anti-tumorous properties.